1. Field of the Invention
The present invention relates to a portable radiographic imaging apparatus and system. More particularly, the present invention relates to a portable radiographic imaging apparatus and system in which causes of a communication failure can be estimated exactly and rapidly.
2. Description Related to the Prior Art
An X-ray imaging system or radiographic imaging system is widely used in medical service in a hospital. The X-ray imaging system includes an X-ray source apparatus or radiation source apparatus, and an X-ray imaging apparatus or radiographic imaging apparatus. The X-ray source apparatus generates X-rays. The X-ray imaging apparatus forms an X-ray image or radiation image of a body of a patient by receiving X-rays transmitted through the body. The X-ray source apparatus includes an X-ray source, a source driver (controllable) and a start switch. The X-ray source applies X-rays to the body. The source driver drives and controls the X-ray source. The start switch inputs a command signal to the source driver to turn on the X-ray source. The X-ray imaging apparatus includes an X-ray image detector or radiation image detector, and a console unit, which receives a command signal for the X-ray image detector and the X-ray image from the X-ray image detector, and displays the X-ray image.
The X-ray image detector has a sensor panel or a flat panel detector (FPD), and detects the X-ray image by converting X-rays transmitted though a body into an electric signal. The X-ray image detector transmits the X-ray image immediately to the console unit which operates for displaying an image visibly. The use of the X-ray image detector is highly advantageous over radiography with an X-ray film or IP cassette (imaging plate cassette), because the image can be checked shortly after the imaging.
Examples of X-ray image detectors include a stationary type installed in an examination room, and a portable type, which is an electronic cassette having a portable housing and the sensor panel contained in the portable housing. A portable X-ray imaging apparatus can be constituted by a combination of the electronic cassette with the console unit of a small form. The electronic cassette is usable in a state fixedly positioned on a floor stand or the like in the examination room for imaging the body in an erect posture or supine posture. Also, the electronic cassette is useful in X-ray imaging of in-patient care in which an operator goes to a hospital room of a patient of limited mobility, namely in a condition without possibility of moving to the examination room.
Also, there is a portable type of the X-ray source apparatus. A movable medical cart is so constructed to carry the X-ray source apparatus. The medical cart is a tool widely used in a hospital. The portable X-ray imaging apparatus is also placed on the medical cart and moved into the hospital rooms one after another for the in-patient care.
JP-A 2011-098025 discloses the X-ray imaging apparatus of a type of radio communication between the electronic cassette and the console unit for transmitting data including the X-ray image. There are various modes of positioning the electronic cassette according to body parts of interest in the body. The electronic cassette may be disposed between the body and a bed, or may be held by hands of the patient. It is unnecessary to connect a cable to the electronic cassette by use of the radio communication, so that the positioning of the electronic cassette can be freely carried out without consideration of a path of the cable.
However, the radio communication is influenced by radio interference of various forms, for example, with radio waves emitted by a portable terminal device of radio communication manually carried by a nurse, physician and the like, and electromagnetic noise created by an electromagnetic medical instrument, such as a thermal treatment device and an electrocautery device. A communication failure such as a delay may be created by influence of the radio interference in a communication environment where the portable terminal device or the electromagnetic medical instrument is present near to the X-ray imaging apparatus of the radio communication. A problem arises in that a constantly high quality cannot be maintained in the communication.
In the X-ray imaging apparatus of JP-A 2011-098025, a transmission speed is measured in the transmission of the X-ray image from the electronic cassette to the console unit, to measure and check the communication environment of the X-ray imaging apparatus. The transmission speed is determined by a data size of the X-ray image and time of the image transmission. In JP-A 2011-098025, the X-ray imaging apparatus produces data of a communication history by storing the transmission speed and a time point of the transmission in a correlated manner at each one event of imaging. Also, it is suggested additionally to store position information of the electronic cassette to the communication history in association with the transmission speed, such as an ID of the floor stand of the apparatus of the electronic cassette.
The communication history is used by a system administrator who administers a computer system in a hospital facility or a network in the hospital facility, such as local area network (LAN), for the purpose of checking the communication environment in the hospital facility and estimating causes of the communication failure. For example, it is likely according to the communication history that delay occurs in a particular time zone in a day. Then the system administrator designates the time zone with high traffic load in the communication, and recognizes that the delay is caused by the high traffic load. Otherwise, the causes of the communication failure are estimated by checking whether there is influence of the electromagnetic medical instrument as a source of the radio interference according to continuation of the time zone of the delay in the communication. It is possible for the system administrator to remove influence of the radio interference according to the estimated causes, for example, by changing a frequency of a channel of the radio communication.
The data size of the X-ray image is large in general, so that influence of the communication failure to the time of the image transmission is considerable. The use of the technique in JP-A 2011-098025 is typically important for the purpose of coping with the communication failure in the X-ray imaging apparatus.
However, there is a problem in the method in JP-A 2011-098025 in that causes of the communication failure corresponding to the communication environment of a newest state cannot be recognized correctly, as a method of producing the communication history by correlating the transmission speed with a time point and a stationary type of the imaging apparatus after measurement of the transmission speed in each event of the imaging.
Positions and the number of the portable terminal devices of radio communication are changed with time by movement of nurses, physicians and the like in the hospital facility with the hospital room for patients. Also, positions and the number of the electromagnetic medical instruments vary according to places in the hospital facility. Therefore, there occur changes in the communication environment in the hospital facility according to time and places. In relation to the communication history disclosed in JP-A 2011-098025, there occurs a time lag between the production and reading of the communication history, as the newest information of the communication history is different from the communication history in the stored form due to the frequent changes in the communication environment. A problem arises in the failure in proper recognition of causes of the communication failure.
A method of measuring the communication environment in JP-A 2011-098025 is only measurement of the transmission speed by data communication. It is likely that the communication failure cannot be estimated exactly even in consideration of the newest state of the communication environment in the communication history. For example, the communication failure including the delay is caused not only by radio waves and electromagnetic noise but also by a blocking object or impropriety of a relative position. The blocking object may be present in the hospital room and blocks radio waves. The relative position constitutes a distance or direction in relation to the electronic cassette and the console unit on a condition of directivity of radio waves. Even though the drop in the transmission speed can be detected, the method of measuring the transmission speed is insufficient for recognizing causes of the drop in the transmission speed, for example, electromagnetic waves, or a blocking object or relative position.
JP-A 2011-098025 discloses the method in which the communication history of plural events (requests) of imaging is referred to for estimating causes of the communication failure. No usable information of the communication history can be obtained for the estimation before completion of the plural events of the imaging. The communication failure cannot be avoided in the imaging in the course of producing the communication history. There is a problem in low rapidity for coping with the communication failure.
As described above, the portable X-ray imaging apparatus is used for the in-patient care by movement in the hospital facility with unexpected fine changes in the communication failure, unlike the stationary type of the apparatus fixed in the examination room. According to a research of the medical service in hospitals, the number of imaging requests for the in-patient care is 20 per day in one hospital facility, and may be increased by 30 as additional urgent requests due to the progress of numerous patients. Only one technician or operator frequently works for imaging in the in-patient care. Thus, a task of 50 or more imaging requests must be performed only by himself or herself in a day. In general, each one event of imaging of the imaging request takes about 5 minutes. It follows the imaging of the in-patient care is carried out in a severely restricted condition of the operator. However, causes of the communication failure cannot be recognized exactly or quickly in the medical service in the hospital facility, so that no appropriate solution for a problem at each one of the hospital rooms can be made for each event of the radiographic imaging.